The evolution of test instrumentation has transitioned over the years from a situation where a single stand-alone box that would typically provide a single dedicated function to one where a multitude of standardized chassis now have the ability to house a plurality of modules, with each module providing a dedicated function so that with a single chassis, multiple functions can be provided.
Bulky test stations for testing complex pieces of equipment using a rack-and-stack approach have largely morphed into significantly smaller footprints through the use of the modular instrumentation. Rack-and-stack implementations may still be used where instrumentation dictates a stand-alone unit (i.e., a display) but over time, even units requiring displays have also gone ‘faceless’ to reduce complexity. The benefits of a modular approach are readily apparent, including for example, redundant functions (control, cooling, power) are eliminated which in turn results in a reduction of size and an increase in overall station reliability.
Over the past 30 years or more, a number of standardized chassis (sometimes referred to as ‘crates’) have been implemented including, but not limited to: MMS, Eurocard, VERSAbus, VMEbus, VXI, VPX, PCI, PXI and AXIe to name a few (the full terms of these abbreviations are known to those skilled in the art to which this invention pertains). While the modular approach has many benefits, one drawback is most systems typically have unused chassis space. Some systems intentionally allocate unused space for future expansion while in others, it is simply the result of how the system was populated. Over time, as existing instrumentation is deemed obsolete by the original equipment manufacturers (OEMs), it is often replaced by a different (or even new) modular form factor which might not be currently implemented within a test station.